A home health attendant savagely murdered a wealthy, 85-year-old Manhattan man in his care by using a chair as a “guillotine” — and then dashed off to Asia with the victim’s money, a law-enforcement source told The Post.

“He took a chair and used it as a guillotine” on Sadhwani’s neck, crushing his larynx after slamming the elderly man with a lamp and knocking him to the ground, the source said.

The 25-year-old killer allegedly swiped thousands of dollars and bought a $4,600, one-way ticket to Malaysia out of JFK, the source added.

The killer was on a Cathay Pacific flight as Sadhwani’s body was discovered two days after the murder, the source said.

The maid showed up for her shift, and when no one answered the bell she called the porter, who came up and opened the door, finding the apartment trashed and the body inside. Detectives from the 17th Squad then launched their investigation.